Home networks are becoming more common and desirable for connecting computers within a home. One type of home network is the home phone line network which uses telephone lines typically installed in residence homes for communication between computers in the home. The Home Phone Line Networking Alliance (HPNA) has published a specification to standardize the behavior of home phone line networks.
FIG. 1 illustrates a home phone line network in accordance with the present invention. The preferred embodiment of the network complies with the Home Phoneline Networking Alliance specification version 2.0 (HPNA 2.0). The network allows multiple computers to communicate through telephone wires typically installed in residential homes. The network comprises a control chip 100. The chip 100 further comprises a Media Independent Interface (MII) 106, a Media Access Control (MAC) 108, and a Physical Layer (PHY) 110. The chip 100 implements the HPNA 2.0 specification. The chip 100 receives a signal containing data packets through the telephone wires via a phone jack 102. There is an analog front end (AFE) 104 which processes the signal between the chip 100 and the telephone wires. The chip 100 then processes the packets received in the signal from the AFE 104, and outputs a signal to the Host MAC 114 or to an Ethernet controller 112.
As is known in the art, the Ethernet controller 112 can be configured to power down, or “sleep”, when not used. A system administration on a remote site may “wake up” the Ethernet controller 112 by sending a frame through the chip 100 and to the Ethernet controller 112. The frame has a particular bit pattern, the “wake pattern”, at a set byte location in the frame. To determine if it should wake, the Ethernet controller 112 counts the bytes in the frame until it reaches the set byte location. The Ethernet controller 112 then attempts to match the bit pattern at the set byte location with the wake pattern. If there is a match, then the Ethernet controller 112 wakes and powers up. Otherwise, the Ethernet controller 112 continues to sleep.
However, under HPNA 2.0, the frame may contain an additional 8-byte Limited Automatic Repeat Request (LARQ) in its header. The LARQ 110 conveys link layer priority information and provides a negative acknowledgment protocol to increase the speed of frame retransmission. The Ethernet protocol used by the Ethernet controller 112 does not recognize or expect the LARQ header. When a HPNA frame with the LARQ header and the wake pattern is sent to the Ethernet controller 112, the Ethernet controller 112 counts the bytes to the set byte location and attempts to match the bit pattern with the wake pattern. However, since the LARQ header has added 8 bytes to the frame, the location at which the Ethernet controller 112 attempts to match the bit pattern is not where the wake pattern is actually located. The Ethernet controller 112 thus does not wake up.
Accordingly, there exists a need for a mechanism to strip the LARQ header to support remote wake up. The present invention addresses such a need.